1. Field of the Invention
This application relates to isolation barriers and more particularly to suppressing common mode transients in communications across isolation barriers.
2. Description of the Related Art
Isolation barriers can be found in many applications such as voltage converters. Isolation barrier refers to an electrical isolation between two domains. Such isolation may be needed because during normal operation a large DC or transient voltage difference exists between the domains. For example, one domain may be “grounded” at a voltage which is switching with respect to earth ground by hundreds or thousands of volts. Another reason for such isolation is based on safety, even when the expected voltage difference between the domains is small in normal operation. An example of this would be in biomedical applications, where electrodes are taped to a patient's body, safety concerns demand an extra layer of protection between the patient and the ground of the measurement device, despite the fact that the measurement device is supposed to be properly grounded.
Isolation barriers typically consist of layers of dielectrics with good breakdown properties. Communication across isolation barriers is commonly done using optical (opto-isolators), inductive (transformer) solutions, or using capacitive isolation circuitry to transmit information across isolation barriers. However, such communication is susceptible to common mode transients that can interfere with the accuracy of the information transmitted across the channel.
Thus, it would be desirable to provide isolation technology with greater immunity to common mode transients.